Effect of esterification with fatty acid of β-cryptoxanthin on its thermal stability and antioxidant activity by chemiluminescence method

β-Cryptoxanthin, a pro-vitamin A carotenoid of potential interest for health, was found in vegetables and fruits in both free and esterified forms. Stabilities of free β-cryptoxanthin (FCX) and its esters including β-cryptoxanthin laurate (CXL), β-cryptoxanthin myristate (CXM), and β-cryptoxanthin palmitate (CXP) against heat were studied by high performance liquid chromatography–mass spectrometry (HPLC–MS). All β-cryptoxanthin fatty acid esters were more stable against heat than FCX. The antioxidant activities of FCX and its esters on superoxide anion, hydroxide radical and singlet oxygen were investigated by the pyrogallol-luminol system, the CuSO4–phenanthroline–Vc–H2O2 system, and OH–NaClO–H2O2 system, respectively, using chemiluminescence (CL) methods in vitro. The antioxidant activities of β-cryptoxanthin fatty acid esters were not significantly different in all methods, furthermore, no synergetic effects amongst them were obtained. These results suggest that esterification of OH groups with fatty acids might not affect antioxidant activity of β-cryptoxanthin but stabilize β-cryptoxanthin against heat degradation.